The invention relates to a centrifugal pendulum and a clutch disk, comprising a pendulum flange, rotational about an axis of rotation, and several pendulum weights pivotally received on the pendulum flange and distributed over the circumference.
In order to reduce torsional vibrations, for example of an internal combustion engine with successive ignitions, caused by the angle of rotation of a crankshaft, torsional vibration dampers and/or torsional vibration absorbers are used, which are optimized for the excitation frequency and temporarily absorb the torque peaks of the torsional vibrations and release them during the torque minima of the torsional vibrations. Here, speed-adjusted torsional vibration absorbers in the form of centrifugal pendulums have proven particularly advantageous, used separately or in a combination with additional torsional vibration dampers. Here, several pivotal pendulum weights are arranged on a part of the torsional vibration system, rotating about an axis of rotation, along a pivotal angle in reference to the rotating part, for example the pendulum flange, distributed over the circumference. These pendulum weights perform vibrations on predetermined paths in the field of centrifugal acceleration when they are excited by cyclic irregularities, such as torsional vibrations. Due to these vibrations, energy is removed from the exciter vibration at the appropriate time and resupplied such that a calming effect is achieved for the excitation frequencies. Due to the fact that both the resonance frequency of the centrifugal pendulum vibration and the excitation frequency are proportional in reference to the speed here the damping effect of a centrifugal pendulum can be yielded over the entire range of frequencies, thus adapted to the speed.
Such centrifugal pendulums are known for example from DE 10 2010 034 812 A1, and can be used in a combination with a torsional vibration damper. For example, a centrifugal pendulum may be located in a clutch disk with or without a torsional vibration damper, with the pendulum flange of the centrifugal pendulum being fastened torque-proof on the hub of the clutch disk. The clutch disk with the torsional vibration damper can here essentially have one or more damper stages switched serially. A first damper stage of a multi-stage torsional vibration damper shows little stiffness and low friction, which are influential at low torque of a drive train, for example at driving conditions such as stop-and-go, idling, or the like. A second damper stage may be activated when a maximum angle of rotation of the first damper stage has been exceeded and serves for damping higher torque, such as during acceleration of the motor vehicle via an appropriate drive train. For this purpose the respective damper stage shows a more steeply inclined characteristic and higher friction.
The centrifugal pendulum is used on such a clutch disk to increase the mass moment of inertia of the transmission input shaft, for example, in case of strongly changing momentums and low speeds, the damping capacity of the first damper stage, for example when the internal combustion engine is shut down without any gear being engaged and when the friction clutch is engaged. This way, the transmission input shaft may be subjected to high accelerations with corresponding noise development.